High lift systems of an aircraft provide the ability to selectively increase the active surface area and the camber of a wing through extending high lift surfaces movably mounted thereon. These may include leading edge slats and trailing edge flaps. With extended high lift surfaces, the lift coefficient of the aircraft may be drastically increased to permit low flight velocities, especially during descent and landing.
In common commercial aircraft, a trailing edge flap system often comprises a central drive unit, which is also known as power control unit (PCU), for transferring rotational power to drive stations, which are distributed in the wing to move the trailing edge flaps. The transfer of rotational power is conducted through a continuous transmission shaft system that extends into the wing by reaching through all drive stations. A safety brake and a monitoring system are usually mechanically coupled with the transmission shaft. Further safety brakes and monitoring sensors are integrated in the drive unit.
Some high lift systems may require dual load paths for the high lift surfaces. The drive stations often comprise geared rotary actuators, which may provide two independent drive or load paths, in order to increase the safety and prevent catastrophic failures under any circumstances. So far, all dual load path solutions for a high lift system comprises duplicate drive elements, which are synchronized with the primary drive elements. They require additional passive brakes and need to be tested for dormant failures. Furthermore, additional system brakes are required within the system.
In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.